Legendary Team Mates
After the credit roll you can go back and battle legandary Pokemon again and if you beat them they will join the rescue team but they might not because of your rank so try and be gold rank or higher.

New Dungeons
After you beat the game and the credits roll, you'll gain access to three new dungeons: Desert Region, Wyvern Hill and Waterfall Pond.

Ranks
Rescue Mission Ranks also go up as you go up in Rescue Team Ranks

if you cannot download trainer then go to Chrome/Firefox's settings, specifically to the Privacy settings and simply unchecking the "Enable phishing and malware protection" option.

Some Game Trainers are sometimes reported to be a Virus or Trojan,
the most common is a keylogger called HotKeysHook or the file
has been packed/protected with VMProtect or Themida and
is recognized as Win32/Packed.VMProtect or Win32/Packed.Themida.
In ALL cases this is a FALSE ALARM as NONE
of the Game Trainers @ GCW contain known malicious code! More info in
the PC
Games FAQ!